1. Field of the Invention
The present invention relates generally to aerodynamic control apparatus and, more particularly, such apparatus used in combination with a wing of an aircraft and, even more particularly, to the wing tip for producing yaw and drag forces.
2. Description of the Prior Art
Over the years, there have been numerous advances in the state of the art relating to aircraft control devices positioned at outboard ends of the wings. A number of patents can be referred to which are generally representative of such advances. For example, an early improvement is provided by U.S. Pat. No. 1,989,291 to Prewitt which discloses an airplane with floating ailerons for roll control encompassing the entire tips of the wings. U.S. Pat. No. 2,210,642 to Thompson discloses a flying wing with fixed stabilizing and control surfaces arranged at the opposite extremities of the wing structure to minimize the possibility of stalling. U.S. Pat. No. 2,846,165 to Axelson discloses an aircraft control system with vertically disposed airfoils at the tip ends of the wings and mounted to pivot about a vertical axis to affect roll and lift control and guard against aileron reversal at high speeds. U.S. Pat. No. 3,067,971 to Dew discloses peripherally disposed drag flaps of unconventional design at the rear of an aircraft or missile to decelerate the vehicle from very high velocities, as upon reentry from space. U.S. Pat. No. 4,247,063 to Jenkins discloses retractable wing-tip mounted vanes for providing both roll control and direct lift control. U.S. Pat. No. 4,382,569 to Boppe et al. discloses a capture device at the tip of a fluid foil such that when provided with relative motion with respect to the fluid in which it is immersed, it intercepts a quantity of the crossflow which is generated by the difference in pressure on the lower surface relative to the upper surface so that lift-induced drag is thereby reduced. U.S. Pat. No. 4,545,552 to Welles discloses an aircraft which utilizes controllable winglets to generate pitching, yawing and rolling moments in flying wing or tailless airframe configurations which are preferably of a swept forward style. U.S. Pat. No. 4,598,885 to Waitzman discloses an aircraft airframe having wings connected to the fuselage by spars of smaller cross section than the wings. Movable winglets may be provided at the outboard ends of the wings.
It was with knowledge of the foregoing state of the technology that the present invention has been conceived and is now reduced to practice.